“It’s the nerve center of the campaign,” said one Democrat with knowledge of the operation. “And a key source in decision making.”

Another former top Obama aide took it a step further, adding that the Clinton’s analytics team “will be the reason Clinton wins in November. There’s nothing like it out there.”

Four years ago, the Obama operation nearly perfected a system of identifying Democratic voters on a district-by-district level.

Put simply, the Obama operation knew where the Democratic voters were in every city and town, and knew how many it needed to deliver to get Obama over the top in swing states such as Virginia, Ohio and Florida.

The focus and fingerprints of the Clinton analytics team—led by Elan Kriegel who served as the battleground states analytics director for Obama for America— is clear in just about every nook and cranny in Clinton’s Brooklyn headquarters.